Effects of Particle Shape on the Instability Behavior of Granular Soils via DEM

The strength and liquefaction characteristics of soil are influenced by the particle shape of the soil. In this paper, the numerical model of stress-controlled was established using PFC2D, and we conducted a series of stress-controlled biaxial compression numerical simulations with particles of different shapes. Then, the simulation results were validated based on laboratory tests, and the impact of particle shape on the macro- and micro-mechanical properties of granular soil was discussed. Finally, the influence of particle shape effects is discussed based on the development process of slope deformation, which is obtained from an engineering example of a cohesionless slope instability by an applied external force. The results show that: (1) Under similar conditions, irregular particle samples exhibit a higher peak stress than regular particle samples. This also means that the instability of regular particle samples occurs in a shorter time; (2) There are differences in contact force, coordination number and form of particle motion in samples with different shapes of particles. Therefore, the differences in shear and instability characteristics between different shapes may be related to the contact mode between particles, the form of motion and other factors; (3) The engineering case indicates that under shape-influenced conditions, slope is more stable when it is composed of irregular particles.